· AQUAPONICS: Aquaponics is a farming method that combines the benefits of aquaculture and hydroponics. A nitrifying bacterium converts fish waste which serves as an organic nutrient source for the plants. The water passes through a hydroponic plant-growing section for filtration which is recirculated back into the fish tank for reuse. With a natural ecosystem that recycles water continuously, an aquaponics system uses 90% less water than traditional farming. Additionally, the system is self-sustaining which requires low maintenance and zero pesticides, fertilizers, or herbicides
The main limitations of this system are that; the often-practised single loop system has challenges in optimizing both fish and plant yields as water quality and nutrient levels differ for both products and must be closely monitored, and it is highly reliant on a consistent power supply
There are numerous successful enterprises practising aquaponics worldwide with the global industry currently valued at $523.7 million and projected to reach $870 million by 2022. In Nigeria, companies are pioneering technology such as; AQUAPONICS NIGERIA in Uyo Akwa-Ibom State, which can serve as a scalable reference.
- COMMUNITY FARMS: A community farm is a multi-functional farm where the land is held “in trust” for a community rather than owned privately. A community group or co-operative governs the land use agreements, and agricultural uses of the land are shared by a community of farmers. The primary focus of a community farm is local food production using sustainable agricultural practices. This system is mainly based on organic farming techniques and can be applied using either open field or greenhouse systems.
The advantages of this system of farming include; job creation, promotion of innovative techniques, community building, food quality, food security, health benefits, training, and education of the farm community. A good example of the efficient use of community farming is in Cuba, wherein in the aftermath of the Cold war, stringent trade restrictions were imposed. The citizens encouraged by the government established an allotment system (land issued to communities with incentivized target crops) and by 2008, 90% of fruits and vegetables consumed were from urban community farms on just 8% of the total landmass. This was facilitated by prudent use of resources, training, and social cohesion. Practices which if properly adopted can be effectively applied in the Nigerian context.
- COMMERCIAL URBAN FARMS: This involves commercial food production by professional farmers using intense and advanced growing systems. The system uses modern inputs and technology such as greenhouses, drip systems and temperature control to produce staples to meet urban market demands. They are usually set up by private enterprises to take advantage of supply gaps, and the high purchasing power of urban dwellers.
The system, however, faces limitations which include; high set-up and operational cost, lack of adequate cold supply chains, the unfavourable purchase price to average urban dwellers, seed supply challenges, and market competition from cheaper but inferior foreign Genetically Modified crops (GM crops). Which has limited the scale impact of this system thus far in Nigeria.
There are numerous commercial urban farms operating in Nigeria such as TENTI GREENS farms in Jos Plateau State. The number and spread of these farms have however proven insufficient to meet urban consumption, with a greater cross-sectoral investment needed to ensure food resilience and security nationwide.
- ROOFTOP/VACANT LOTS FARMING: As implied by the name, this system uses rooftops and vacant lots for food production utilizing various farming techniques that maximize output in limited space, such as vertical farming techniques and crate farming. This system’s main advantage, apart from the fact it uses up space which would have been lying idle, is the effective use of household waste as compost in food production which can aid in city waste management. It also enhances urban landscapes and makes them more eco-friendly.
Rooftop farming has been widely accepted in both developed and developing cities across the globe, as a possible solution to urban food shortages, and environmental challenges. Examples include; ‘Brooklyn Grange’ the world’s largest rooftop garden in New York, ‘And Dakpark in Rotterdam, a vegetable garden, restaurant, and park on top of a shopping centre. And Aeroroots Pvt Ltd has successfully applied its ‘Aeroroof’ systems in Godawari, Nepal.
While there are noted limitations such as; the effect of rooftop farming on the weight and structure of building roofs, the high cost of membrane (water systems) installation, and insurance/safety issues.
This system will be very helpful in high population-dense cities with a significant number of high-rises such as; Lagos, Abuja and Port Harcourt to ensure sustainable fresh food for residents and restaurants.
- AGRO PARKS: These are clusters of agricultural activities where various links of the food chain are located in close proximity. The concept has been developed to apply industrial ecology in the agricultural sector.
The benefits of this system include; creating a closed production system where inputs and outputs of value chains are maximized, reduction in transport cost, biodiversity/ecological benefits, bridging the gap between producer and consumer, and sustainable socio-economic environments.
The limitations of this system’s adaptation in Nigeria include; Insufficient volume/ varieties of crops for processing, high production cost, inadequate infrastructure for scale, bureaucratic bottlenecks, low yields and post-harvest losses, unfavourable tax policies, a shortage of skilled labour and inadequate quality control.
A great example of successful implementation of this system is the ‘Bio-Park Terneuzen’ in the Netherlands, where the company ‘WarmCO2’ produces vegetables in glasshouses using the heat and carbon dioxide (CO2) from industrial companies next door at the same industrial site. A similar system can be adopted where various value chain industries can be co-located in a specific hub (e.g. Sugarcane hub in Adamawa State, Yam/fruit hub in Benue State) to ensure effective supply chains and reduced logistical cost of goods.